1. Field of the Invention
The present invention relates to engine starters, i.e., to apparatus for starting an internal combustion engine.
2. Related Background Art
The conventional starters for manually starting the internal combustion engine are of a type in which a starting rope is wound on a pulley attached to the crank shaft of the internal combustion engine and in which an operator pulls the starting rope to rotate the crank shaft, thereby starting the internal combustion engine. A one-way clutch is interposed between the pulley and the crank shaft whereby the starters are configured so that when the pulley is rotated in a direction necessary for starting, the crank shaft can rotate in the same direction with the rotation of the pulley but so that when the pulley is rotated in the opposite direction, the crank shaft can not rotate. Further, the pulley is equipped with a spiral spring or power spring for storing energy with pullout of the starting rope, and the combination of this spiral spring with the foregoing one-way clutch performs the function of automatically rewinding the starting rope pulled out, onto the pulley without rotating the crank shaft.
In the conventional starters as described above, since the operator""s pull-force on the rope is directly transmitted from the starting rope through the pulley to the crank shaft, the load in the compression stroke of the internal combustion engine is directly transmitted to the starting rope, whereby the force for pulling the rope may be variant. Namely, during the action of pulling the starting rope, the load in the compression stroke of the internal combustion engine is transmitted pulsewise to the rope; a strong rope pull-force is necessary before the end of the compression stroke, whereas only a weak rope pull-force is enough after the end of the compression stroke up to the next compression stroke.
The internal combustion engine will fail to start up unless the starting rope is pulled so as to rotate the crank shaft at a rotational speed over a certain level. In addition to the foregoing variance of the rope pull-force, the load was heavy on the operator and it was hard for a powerless operator to start the internal combustion engine.
Further, with the conventional starters, there was a knack in rotating the crank shaft at a fast rotational speed, e.g., to start pulling the rope after the piston of the internal combustion engine was adjusted at the compression position (near the position of the top dead center), and, therefore, the operator had to be skilled to some extent.
It is, therefore, an object of the present invention to provide engine starters capable of securely starting the internal combustion engine even by an almost constant, weak pull-force on the starting rope.
For accomplishing the above object, the present invention provides a starter for starting an internal combustion engine, in which energy is stored in an energy storing spring housed in a case fixed relative to the internal combustion engine with pullout of a starting rope from the case and in which the spring energy stored in the energy storing spring is released to rotate a crank shaft of the internal combustion engine, thereby starting the internal combustion engine, wherein the starter is constructed so that the spring energy stored in the energy storing spring is released at the start of rewinding of the starting rope which has been pulled out from the case.
More specifically, in the present invention, the starting rope is wound on a reel rotatably mounted in the case. The crank shaft of the internal combustion engine is disconnectably connected through a one-way clutch to a rotor rotatably mounted in the case, and the energy storing spring is arranged so as to store the energy as the rotor rotates relative to the case in a predetermined direction. The engine starter according to the present invention further comprises engaging means for engaging the reel with the rotor, and engagement controlling means for controlling the engaging means. The engagement controlling means controls the engaging means so as to engage the reel with the rotor with pullout of the starting rope from the reel, whereby a torque of the reel is transmitted to the rotor to store the energy in the energy storing spring. The engagement controlling means controls the engaging means so as to release the engagement between the reel and the rotor at the start of rewinding of the starting rope onto the reel after the pullout of the starting rope, whereby a restoring force of the energy storing spring is transmitted through the rotor and the one-way clutch to the crank shaft to rotate the crank shaft.
In this configuration, the reel is engaged with the rotor with pullout of the starting rope to store the energy in the energy storing spring through rotation of the rotor. On this occasion, the one-way clutch disengages the rotor from the crank shaft of the internal combustion engine, so that the pull on the starting rope is determined by only the spring force of the energy storing spring. Therefore, the starting rope can be drawn out by constant force. Since the great load in the compression stroke of the internal combustion engine is not transferred to the starting rope, the rope pull is relieved by that degree. During rewinding of the starting rope the restoring force of the energy storing spring automatically rotates the rotor and the torque thereof rotates the crank shaft through the one-way clutch. Therefore, the crank shaft rotates at a speed determined by the energy storing spring, so as to be able to start the internal combustion engine securely.
It is preferable to provide a rope rewinding spring for storing energy with pullout of the starting rope from the reel and for rotating the reel so as to rewind the starting rope pulled out, onto the reel, because the rope rewinding spring automatically rewinds the starting rope up.
Various forms are conceivable for the engaging means for engaging the reel with the rotor and for the engagement controlling means for controlling the engagement and disengagement by the engaging means.
For example, where the reel and the rotor are arranged as coaxial with each other, a conceivable configuration is such that the engaging means comprises a plurality of teeth provided at the rotor; and a pawl an intermediate portion of which is rockably mounted on the reel and a first end of which is engageable with the teeth and that the engagement controlling means comprises a first rocking member mounted so as to be adjacent to the first end of the pawl and rockable on the reel, said first rocking member being arranged to push the first end of the pawl to engage the pawl with the teeth; a second rocking member mounted so as to be adjacent to a second end of the pawl and rockable on the reel, said second rocking member being arranged to push the second end of the pawl to release engagement of said pawl with the teeth; cam means provided at the case and arranged to engage with the first rocking member and the second rocking member to rock these rocking members; and a spring arranged to bias the first rocking member and the second rocking member toward engagement with the cam means. In this configuration, the cam means is arranged to rock the first rocking member to rock the pawl to a position of engagement with the teeth with pullout of the starting rope from the reel and is arranged to rock the second rocking member to rock the pawl to a position of disengagement from the teeth with rewinding of the starting rope onto the reel.
Further, where a spline member is provided so as to be coaxial with the rotor and to be rotatably mounted in the case and where the reel is arranged to be spline-coupled to an outer periphery of the spline member so as to be movable to near or away from the rotor, a conceivable configuration is such that the engaging means comprises a claw provided at either the reel or the rotor; and a recess provided at the other of the reel and the rotor so as to be fitted with the claw when the reel is located near the rotor and that the engagement controlling means comprises a base mounted so as to be coaxial with the reel and rotatable in the case, said base being arranged to rotate together with the reel; base fixing means for fixing the base relative to the case at the start of pullout of the starting rope and at the start of rewinding of the starting rope; and a spiral cam provided between the base and the reel, said spiral cam being arranged to move the reel to near the rotor as the reel is rotated in a pullout direction of the starting rope.
A preferred configuration of the foregoing base fixing means comprises a plurality of teeth provided at an inner peripheral surface of the case; a pawl mounted so as to be rockable on the base and arranged to be engageable with the teeth; a spring arranged to bias the pawl so as to engage the pawl with the teeth; and a piece provided at the reel, said piece being arranged to engage with the pawl with rotation of the reel to transmit a torque of the reel to the base and said piece being arranged to push the pawl to release engagement between the pawl and the teeth.
Further, where the reel and the rotor are arranged as coaxial with each other, preferred configurations of the engaging means and the engagement controlling means other than the above are as follows.
Namely, a further configuration is such that the engaging means comprises a projecting portion provided at the rotor; and a pawl mounted so as to be rockable on the reel and arranged to be engageable with the projecting portion and that the engagement controlling means comprises a V-groove pulley fixed to the case; a friction wire frictionally fitted in the V-groove pulley and connected to the pawl, said friction wire being arranged to be displaced relative to the V-groove pulley with pullout of the starting rope from the reel to rock the pawl so as to engage the pawl with the projecting portion; and a release pawl mounted on the case, said release pawl being arranged to go into contact with the pawl with rewinding of the starting rope onto the reel to rock the pawl so as to disengage the pawl from the projecting portion.
Another conceivable configuration is such that the engaging means comprises a projecting portion provided at the rotor; and a pawl mounted so as to be rockable on the reel and arranged to be engageable with the projecting portion and that the engagement controlling means comprises a V-groove pulley fixed to the case; a friction wire frictionally fitted in the V-groove pulley and connected to the pawl, said friction wire being arranged to be displaced relative to the V-groove pulley with pullout of the starting rope from the reel to rock the pawl so as to engage the pawl with the projecting portion; a cam surface formed at the case; and a release pawl mounted on the pawl, said release pawl being arranged to rock the pawl in cooperation with the cam surface with rewinding of the starting rope onto the reel so as to disengage the pawl from the projecting portion.
A further potential configuration is such that the engaging means comprises a plurality of teeth provided at the reel; and a pawl mounted so as to be rockable on the rotor and arranged to be engageable with the teeth and that the engagement controlling means comprises a spring arranged to bias the pawl so as to engage the pawl with the teeth; a protruding piece provided at the case; and a rocking member mounded so as to be rockable on the rotor, said rocking member being arranged to rock in contact with the protruding piece with rewinding of the starting rope onto the reel to rock the pawl so as to disengage the pawl from the teeth.
Still another potential configuration is such that the engaging means comprises a plurality of teeth provided at the rotor; and a pawl mounted so as to be rockable on the reel and arranged to be engageable with the teeth and that the engagement controlling means comprises a rocking member mounted so as to be rockable on the reel, said rocking member being arranged to go into contact with the pawl to rock the pawl, so as to effect engagement with or disengagement from the teeth; a V-groove pulley fixed to the case; and a friction wire frictionally fitted in the V-groove pulley and connected to the rocking member, said friction wire being arranged to be displaced relative to the V-groove pulley with pullout of the starting rope from the reel to rock the rocking member so as to rock the pawl to a position of engagement with the teeth and said friction wire being arranged to be displaced relative to the V-groove pulley with rewinding of the starting rope onto the reel to rock the rocking member so as to rock the pawl to a position of disengagement from the teeth.
When the energy storing spring is a spiral spring, an effective configuration is such that the spring is mounted on the case while being undetachably housed in a spring case.
These and other features and advantages of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings wherein there are shown and described illustrative embodiments of the invention.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.